Iron Man may have made box office history with its $98.6 million opening last weekend. But the film’s success has also solidified the directing career of Jon Favreau, the actor who first endeared himself to hipster filmgoers as the lonelyhearted buddy of the so-money Vince Vaughn in 1996’s Swingers, which Favreau also wrote.

Favreau’s directing career took off in 2003 with the Christmas comedy Elf (which also launched Will Ferrell onto the A list). Although a box office stumble with the board-game-comes-alive yarn Zathura followed, he soon found himself helming Iron Man, the maiden film for the newly independent Marvel Studios. The studio signed off on Favreau’s bold decision to cast Robert Downey Jr. — an actor who had never had a film gross $100 million in its entire run — as the rakish arms developer Tony Stark. And as we all know by now, the gamble paid off: Iron Manraked in nearly $100 million between last Friday and last Sunday, the second-best debut ever for a non-sequel.

EW.com caught up with Favreau to talk about his movie’s box office explosion, Downey’s newfound superstardom, the prospects for Iron Man 2, and other members of the Marvel universe. And be forewarned: There are spoilers ahead!

ENTERTAINMENT WEEKLY: How are you feeling today?JON FAVREAU: I am doing good. It’s nice when it works out this way. It doesn’t happen that often! [Laughs]

This is just the second time that a non-sequel has grossed this much on its opening weekend. Yeah, you know it’s amazing, it’s the biggest thrill. I remember the first [time I felt like this] was when I got my Chevy commercial and I got in SAG. That was a big one back in Chicago. Then when Swingers got bought, that was a huge changing moment for me. And then Elf — when Elf took off, I felt it more, and I didn’t think I could feel this way again, but I do. I do now. And Robert and I are just very, very appreciative and humbled by the whole thing. It’s been a really wonderful, wonderful experience.

When did you first know that the box office was going to come back so huge? Well, I think the first moment, it was sort of when Robert and I went around the world together [publicizing the movie]. We spent about three weeks traveling, and when the feedback was positive all around the world, that was the first sense that we had done well. And then when the reviews came out I felt very good, because if the film is seen as a good film regardless of how it does commercially, you’re still going to work — you’re not going to alienate your fans, you’re not going to alienate your audience out there, so that was a big sense of relief. But then the tracking came in and we were definitely in good shape. You know, ”good shape” on a movie like this has to be a whole level of success beyond what any other film I’ve worked on is judged against. It’s very scary that we could have made $60 million and been a very profitable film — and been considered a failure. That was a little bit daunting.

NEXT PAGE: There’s definitely a lot of ideas that we all have now…. This type of movie is based on serialized materials, so it lends itself very easily to [many different sequel possibilities]